Apparatus for electrical treatment of gases



L. DANE.

FILED MAR. 14, 1918.

APPARATUS FOR ELECTRICAL TREATMENT OF-GASES.

Jan. 16, 1923.

btocuevp M m W Patented Jan. 16, 1923.

UNITED STATES PATENT. OFFICE.

LOUIS DANE, 0F BROOKLYN, NEW YORK, ASSIGN'OR T0 RRsRARoH CORPORATION, OFNEW YORK, N. Y., A CORPORATION OF NEW YORK.

APPARATUS FOIt ELECTRICAL TREATMENT OF. GASES.

Application filed March 14, 1918. Serial No. 222,423.

To all whom it may concern:

Be it known that I, LOUIS DANE, a citizen of the United States, residingat Brookl in the county of Kings and State of Lew York,- have inventedcertain new and useful Improvements in Apparatus for EleotricalTreatment of Gases, of which the following is a specification.

The'present invention relates to apparatus for the electrical treatmentof gases and more particularly to apparatus for the electricalprecipitation of suspended particles from fluid streams.

In the practical use of electrical precipitators it is often found thatall disruptive charges occur in one particular part of the treaterapparatus. With some gases it was found that the spark-over occurredadjacent the entrance end of the trea-ter chamber and with others at theexit end thereof. It was therefore not possible under these conditionsto obtain a uniform field of electric stress.

It is the object of this invention toprovide means whereby the electricstrength of the gas path between the electrodes is substan tiallyuniform throughout the length of the electrodes.

I accomplish this object by so constructing and dimensioning theelectrodes that the electrical field varies in proportion to theconductivity of the fluid stream as the fluid stream passes through theelectric field.

For a fuller understanding of the invention reference is had to theaccompanying drawings in which Figure 1 represents one form ofprecipitator embodying the invention;

Figure 2 is a fragmentary view of another form;

Figures 3 and 4 are elevation and plan view respectively of amodification of the apparatus shown in Figure 1 Figures 5 and 6 areelevation and plan view respectively diagrammatically illustrating stillanother form and Figure 7 is a fragmentary sectional view of amechanical construction for carrying into effect the idea disclosed inFigures 5 and 6.

In Figure 1 legs 2, uprights 3 and braces 4: represent a conventionalarrangement for supporting the flue or collecting electrode 5 whichterminates at its lower end in a hopper 6 and is open at its top.Through an conveniently supported on a cross-frame 9 resting oninsulators 10 which in turn are mounted on the top of the generalsup-portmg structure. The wire 8 carries at its lower end a weight 11 tokeep it taut and hold it in position. A conveyer 12 may be provided atthe bottom of the hopper for removing the collected particles. Thestructure so far described is merely a conventional arrangement toindicate the relation of the precipitator elements and may be varied innumerous ways. I

- The collecting electrode in the particular form of apparatus is shownas tapering from bottom to top. This form of the flue structure isintended for the treatment of gases which carry electrically conductiveparticles.

When the gases enter, the fluid stream has therefore a minimumdielectric strength and as the stream reaches the top, when nearly allthe suspended particles'are precipitated, the dielectric strength hasincreased to a certain limit. In the zones inter-mediate the ends thedielectric strength which varies with the content of suspended particleshas lecting electrode and 16 the discharge electrode, the dischargedistance is varied by providing on the discharge electrode prongs I ordisks 1'? of gradually varying diameter.

It is a ain assumed that the "as to be treated contains electricallyconductive suspended in the gas stream. At the bottom particles v V ofthe flue the discharge distance is that betom. This distance is suchthat spark-over occurs there at a voltage just above that at which it isfound desirable to run the precipitator.

The diameters of the successive disks 17 are then so chosen that thecritical disruptive voltage is the same throughout the treater.

In Figure 2 the diameters of the disks 17 are shown as increasing fromthe bottom to near the top of the flue and then decreasing again. Bythis arrangement the danger of spark-over at the top is considerablydecreased. As the gases approach the exit end of the flue, they aresubstantially clean and it is not absolutely essential that the electricstress should in this zone be kept near the critical point of disruptivedischarge. There is, moreover, at the end of the flue a. tendency tospark-over due to the sharp edge of the flue. By increasing thedischarge distance again at the edge of the flue, this danger isavoided. The same effect could be obtained,

of course, by rounding the edge of the flue, but it is much simpler,mechanically, to make the adjustment in the manner indicated.

Figures 3 and 4 depict an arrangement similar to that shown in Figure 1,but having the upper portion 21 of the flue 2O flaring outwardly, partlyfor the purpose mentioned in connection with the description. of Figure2 and partly for the purpose of admitting of the introduction of aflushing system. A nozzle 22 connected to acsupply pipe 23 may be usedto flush the walls of the collecting electrode 20 to continuously removethe particles collected thereon or) for other purposes. This nozzle ispreferably arranged in a direction substantially tangential to the wallof the flue so as to force the liquid, for instance water, around theglhole flue and form a substantially uniform m. Figures 5 and 6 showsimple outlines an electric treater in which the discharge distancebetween the discharge electrode 33 and" the collecting electrode isvaried by varying the diameter of orificed plates forming a. part of thecollecting electrode. The flue may be angular, as indicated, or round orof any desired form. The square plates 30 have central orifices 31. Itis assumed again that the gases enter at the bottom of the treater andcontain electrically conductive suspended particles. For this reason thebottom plate has the greatest orifice and the orifices in the otherplates gradually decrease in diameter toward the upper end in proportionto the change of dielectric strength of the gas in its passage throughthe treater, as has been explained in connection with the description ofthe other figures.

Adjacent the upper end of the flue, the

' carry a charge.

orifices increase again in diameter for a purpose previously stated. Bythis arrangement, like in the previously described arrangements, theelectric stress may be made substantially uniform throughout thetreater.

Figure 7 shows a practical embodiment of the idea disclosed in Figures5and 6. The treater flue maybe built up of a plurality of plates 38forming the Walls thereof. Bars or blocks 10 may be uniformly spacedalong two opposing plates 38 to define transverse grooves for receivingthe orificed plates 41. The blocks 40 may be secured to the plates inany suitable manner as for instance by means of screws 39. While thestructure may be formed in various ways, I prefer to permanentlyassemble three -walls of the flue, two of which carry the blocks 40 aspreviously indicated. The plates 41 can then be easily placed inposition in the grooves and when they are in place the fourth plate 38can be attached to complete the flue. By this construction it is easy toremove the orificed plates 41 for cleaning. The operation is obvious.The uniformity of the electric field in point of strength does not onlylead to a high degree of efficiency and economy, but also eliminates toa great extent the undesirable local eddies and other disturbances whichare due to different stresses existing in the electric field.

While the change of dielectric strength was in the foregoing assumed tobe due to the presence of electrically conductive suspended particles inthe gases, there may be other causes for such changes Gases andparticles may enter with residual electric charges and leave with thesecharges neutralized, increased or changed. Blast furnace gases and otherhot gases are apt to Gases may enter without appreciable charge and takeon and hold one in thecourse of their passage. Also the change oftemperature of the gases may bring about a difference in the electricalcharacteristics of the gases and such change may take place whilepassing through the treater chamber.

The present disclosure is not intended to cover all possible embodimentsof which the invention is susceptible. Obviously various changes may bemade in the forms of the electrodes within the scope of the disclosure.

I claim i 1. An apparatus for the electrical treat- -ment of gases,comprising a flue element actral'ity of plates connected to one of saidelec trodes for gradually varying the dielectric distance therebetween.

3. In apparatus for the electrical treatment of gases, comprising a flueelement acting as a collecting electrode, a discharge electrodeextending into said flue and a plurality of plates on the said flue forgradually varying the dielectric distance between the said electrodes.

4:. In apparatus for the electrical treatment of gases, comprising aflue element, a plurality of plates transversely of said fluehavingaligned orifices of gradually varying diameter and a dischargeelectrode ex- Eending into the space defined by said orices.

5. In apparatus for the electrical treatment of gases, comprising a flueelement, a

plurality of closely spaced plates transversely of said flue havingaligned orifices of gradually varying diameter and a discharge electrodeextending into the space defined by said orifices.

.6. An apparatus for the electrical treatment of gases, comprising aflue element acting as a collecting electrode, a plurality of orificedplates in the flue, said orifices being formed to define a substantiallyconical passage terminating at its top in a flaring mouth, and adischarge electrode extending through said mouth into the passage.

In testimony whereof I aflix my signature in presence of two Witnesses.

, LOUIS DANE. WVitnesses A. F. MEs'roN,

J. HUFF.

